Depending on the location of use, various types of soil deposit on the hard surfaces of baths, washstands, restrooms, and other damp locations. For example, the soil in baths comprises proteins and other nitrogenous compounds, fatty acid metal salts, or the like; the soil in washstands comprises fatty acid metal salts and the like; and the soil in restrooms comprises urolith deposits, soil that is based on fecal matter, urine, and other types of excrement, and the like. In addition, these hard surfaces undergo repeated drying after coming into constant contact with tap water, so silicate scale or carbonate scale derived from tap water are concentrated and deposited locally, producing soil commonly referred to as “water spots” or “water stains.” In particular, the restroom bowls, washbowls, and other ceramic fixtures, as well as mirrors and other glass surfaces in restroom areas are hydrophilic, and therefore tend to be covered with water stains.
If such water stains continue to build up over a long time, the water stains bond firmly with the hard surfaces, and not only does removal become more difficult, but the components of the water stains tend to become a breeding ground for mold and germs together with other types of soil, and sanitary problems are encountered. Initial water stains can be removed relatively easily by careful cleaning, but currently the situation is such that the frequency of cleaning tends to decrease due to the streamlining of cleaning operations.
In view of this, a need exists for detergents that have the ability (anti-soiling effect) to reduce deposits of water stains and other types of soil, and detergents that clean and at the same time endow cleaned surfaces with the anti-soiling effect have come to be developed in order to prevent water stains from firmly adhering to hard surfaces. Detergents endowed with the ability to form films on the cleaned surfaces and to provide an anti-soiling effect by the incorporation of specific organopolysiloxanes into the detergent composition have been proposed as products that combine such an anti-soiling effect.
Examples of disclosed detergents that combine an anti-soiling effect and contain such organopolysiloxanes include compositions for bathtub cleaning that contain amino-modified organopolysiloxanes and nonionic surfactants, inhibit redeposition of water-formed deposits, and have protective action on bathtub materials (refer, for example, to Japanese Patent Application Laid-open No. S51-83608), as well as detergent compositions that contain specific organopolysiloxane and provide delustering and surface protection to bath fixtures (refer, for example, to Japanese Patent Application Laid-open No. H3-197596). Also disclosed is a detergent composition for the desoiling and antibacterial cleaning of hard surfaces that contains specific cationic surfactants, cation-based bactericidal agents, and hydrophilic organopolysiloxanes and has an anti-soiling effect and antibacterial action (refer, for example, to Japanese Patent Application Laid-open No. 2000-198999).
Japanese Patent Application Laid-open Nos. S51-83608 and H3-197596 disclose detergent compositions that have excellent anti-soiling effects and detergency with respect to water-formed deposits and soil, but there is no mention of an anti-soiling effect on water stains, nor is there any disclosure made concerning sustained anti-soiling effects or storage stability, which are believed to be important in practical terms. Japanese Patent Application Laid-open No. 2000-198999 discloses a detergent composition that has an excellent anti-soiling effect on water stains.